I think Yours idea is in general not supported by PLCs, because You need to keep some standards while building automation system, so some of the wireless fieldbuses would be maybe more appropriate, BUT
I think, that You can use protocol gateway to make it Your own way e.g. XBee to Ethernet
have a look on this site, maybe it will be helpfull:
If I understand correcly, lots of researcher still working on your idea. G3 and 1901.2 can handle 802.15.4 MAC layer, especially with Ipv6 for easly entegration between plc and low power low bandwith wireless protocols. I remember a paper about similar our interest:
Hello A.T., I have read the paper You suggested, but there is a misunderstanding, we were talking about PLC - Programmable Logic Controller and the paper uses PLC as Power Line Communication. However, I'm sure that some ideas from the paper could be useful.
I have performed in the past some experimental test with Zigbee based sensors which sent data to a Centralized system with a PLC attached to a Zigbee module. This PLC was implemented with an Arduino ONE and XBee Shield and it was connected via RS232 with a Host running Processing with Firmata protocol.